Update note.md with modern documentation commands

- Add yard to Gemfile
- Move development dependencies from gemspec to Gemfile

Author: kojix2

Gemfile

@@ -2,3 +2,10 @@ source 'https://rubygems.org'
 
 # Specify your gem's dependencies in narray-devel.gemspec
 gemspec
+
+group :development do
+  gem 'rake', '>= 12.3.3'
+  gem 'rake-compiler', '~> 1.1'
+  gem 'test-unit'
+  gem 'yard'
+end

doc/note.md

@@ -13,11 +13,6 @@ bundle exec ruby test/bit_test.rb
 
 ## YARD documents generation
 
-(in advance, install yard gem)
-
-  ```shell
-$ cd "${HOME}/.gem/ruby/2.?/gems/numo-narray-0.9.?.?/ext/numo/narray"
-$ make doc
-yard doc *.c types/*.c
-...
+```shell
+bundle exec rake doc
 ```

numo-narray.gemspec

@@ -27,8 +27,4 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ["lib"]
   spec.extensions    = ["ext/numo/narray/extconf.rb"]
-
-  spec.add_development_dependency "rake", ">= 12.3.3"
-  spec.add_development_dependency "rake-compiler", "~> 1.1"
-  spec.add_development_dependency "test-unit"
 end